Bags made of plastic sheet material have gained wide acceptance for use in supermarkets. Such bags are preferred because of their high strength, light weight, moisture resistance and relatively low cost. However, the plastic sheet material from which such bags are made exhibits very little stiffness, so that a plastic shopping bag cannot be filled in the same manner as a paper one (i.e. by standing the bag up in an open position). It has therefore become the standard practice, with plastic shopping bags, to utilize some form of stand to support the bag while it is being filled. However, the use of supporting racks has introduced a whole series of problems of its known.
In order to use a bag rack effectively, each of the bags should be flat, and a stack of bags should be formed into a "bag-pack" for mounting on the rack. Individual bags can then be removed from the mounted bag-pack and filled until all the bags in the bag-pack are used up, at which time a new bag-pack is mounted on the rack.
One well-known type of plastic shopping bag is the so-called handle bag, which consists of flat front and rear surfaces joined by a gusset at either lateral edge and a handle portion projecting upwardly on either edge of the front and rear surfaces. In order to form a bag-pack, each bag is provided with a detachable tab portion between the two handles, and the stack of bags forming the bag-pack is joined by sealing the tabs together, for example, by driving a heated pin through the tabs. A bag-pack is mounted on the supporting rack by providing means for supporting the joined tabs, and separate arms are provided for supporting each of the bag handles. Typically, holes are punched through each of the bag handles so as to permit them to be placed on forwardly projecting arms positioned on the supporting rack, with each arm extending through the holes in one stack of bag handles. Although this makes it convenient to load a bag by sliding it forward on the arms, such bag and bag-pack construction suffer from two major shortcomings.
First of all, punching holes through the bag handles tends to weaken the handles. When the bags are filled to the degree that is common in supermarkets, the weight of the contents causes tears to develop in the handles which emanate directly from stress points in the holes. Usually, the handles on such a bag will tear under normal loading conditions, while it is being carried by a shopper. This is particularly likely if the bag is made of a low density plastic sheet material, which is now common.
A second problem encountered with bag-packs of this type is that they can only be mounted on the supporting rack if the stacked handles of the bags are retained together. Otherwise, the handles separate while the attendant is mounting the bag-pack on the rack, and it becomes inconvenient and tedious to place the individual handles on the supporting arms. However, it is not enough that the handles be joined, since it also necessary that the handles of a bag separate readily from the bag-pack once it is filled. It has been suggested that the handles on each side of a bag-pack be provided with detachable portions which are joined together in the same manner as the bag tabs (see, for example, U.S. Pat. No. 4,676,378, granted to W. H. Baxley, et al. on June 30, 1987). However, this introduces additional steps which complicate the manufacturing process and make it more expensive.
Broadly, it is an object of the present invention to provide a plastic bag and bag-pack which avoid the shortcomings of prior art articles of this type. It is specifically contemplated that the bag-pack be capable of being conveniently mounted on a supporting rack so that the individual bags will be held in position on the rack while being filled, without weakening the handles of the bag.
It is also an object of the present invention to provide a method for manufacturing a bag-pack of the type described.
It is yet another object of the present invention to provide a bag and bag-pack which are convenient and reliable in use, yet relatively inexpensive to manufacture.
In accordance with the present invention, a plurality of bags, each having an upright handle at either lateral edge thereof, is formed into a bag-pack, and the bag-pack is retained on a supporting rack by providing upright slits in the handles of each bag. The applicants have found that, unlike holes which are formed in the bag handles, upright slits do not cause weakening of the handles. As used herein, the term "slit" will be understood to be a cut placed in the material of the bag which causes separation of the material, but does not remove material. In addition, it has been found that, if the handles of the bags comprising a bag-pack are punched with a heated pin having a diameter no larger than approximately three thirty-seconds of an inch, the handles of the bags comprising the bag-pack will be welded together sufficiently to permit convenient insertion of the arms of the supporting rack through the slits in the bag handles, without substantially weakening the bag handles. At the same time, the individual bags will be readily detachable from the bag-pack, after being filled, if the pin is heated by being placed in a passageway in a block of metal heated to a temperature in the range of about 250.degree.-260.degree. F. The passageway should be long enough to receive at least a forward portion of the pin corresponding in length to approximately the stacked height of the bag-pack.